Coil and stationary magnet mounting for an electromagnetically operated device



, March 17, 1970 K. J. MARIEN r COIL AND STATIONARY MAGNET MOUNTING FORAN ELECTROMAGNETICALLY OPERATED DEVICE Filed Sept. 12, 1968 uvvs/vron.KENNETH J. MARIEN United States Patent 3,501,723 COIL AND STATIONARYMAGNET MOUNTING FOR AN ELECTROMAGNETICALLY OPERATED DEVICE Kenneth J.Marien, Wauwatosa, Wis., assignor to Square D Company, Park Ridge, III.,a corporation of Michigan Filed Sept. 12, 1968, Ser. No. 759,381 Int.Cl. H01h 9/02, 13/04 US. 'Cl. 335-202 Claims ABSTRACT OF THE DISCLOSUREAn electromagnet support and mounting structure wherein a singlemounting screw maintains a stationary magnet part in position on amounting base and moves a lever to resiliently maintain the magnet coilin position on the stationary magnet part when the mounting screw istightened in a threaded opening in the base.

This invention relates to electromagnetically operated devices and ismore particularly concerned with an improved mounting for a stationarymagnet part, a magnet coil and an armature of an electromagnet in anelectromagnetically operated device.

Electromagnetically operated devices, such as switches and the like, ofthe gravity drop-out type, conventionally include a base which issecured on a mounting panel and which provides a support for theswitching contacts and an electromagnet which operates the switchcontacts. As a large number of switching devices may be mounted on asingle panel, space requirements dictate that the size of the individualdevices be as small as practicable without sacrificing their switchingreliability and operational life. To accommodate the size requirementsof the devices, the magnet structures tend to generate excessive heatwhen the devices are energized for long periods of time. In somedevices, the heat generated by the magnets is dissipated by mounting themagnet structures on bases which are made of die cast metal. Anotherrequirement which the devices are required to satisfy is that the magnetcoil must be readily removable for service or replacement purposes. Inmany prior art devices elaborate structures are used to satisfy thisrequirement. In the device according to the present invention, themanipulation of a single screw will permit replacement of the entiremagnet structure or the magnet coil, as desired. Additionally, one ofthe problems encountered in electromagnetically operated devices, is theshock accompanying the energization of the magnet is transmitted to thecontacts of the device and causes the contacts to bounce and thus reducethe electrical life of the device when the device is operating to switchelectrical loads. In the device according to the present invention, theshock accompanying the engagement of the movable magnet with thestationary magnet part upon energization of the magnet coil is absorbedby a novel structure which does not interfere with the removal orinstallation of the magnet structure or the heat dissipating propertiesof the device. Another feature included in the device according to thepresent invention is the use of an encapsulated coil. While encapsulatedcoils are well known, and are frequently used in devices of the type towhich this invention relates, the novel arrangement for mounting thecoil as used in the device according to the present invention,resiliently positions the coil to compensate for dimensional variationsin the coils without sacrificing the ease with which the coil may beremoved and replaced from the structure.

It is an object of the present invention to provide anelectromagnetically operated device, such as a relay, with a novelstructure which will permit the electromagnet in- 3,501,723 PatentedMar. 17, 1970 cluding the magnet coil to be readily removed and replacedand which will minimize the transmission of the shock accompanying theoperation of the electromagnet to the switching contacts of the device.

Another object is to provide an electromagnetically operated switchingdevice, such as a relay, with a die cast base which will dissipate theheat generated within the electromagnet, will position a shock absorbingstructure to minimize transmission of shock forces to the switchingcontacts of the device when the electromagnet is energized, and whichwill position the electromagnet so the coil and other components of theelectromagnet may be readily removed and installed upon manipulaion of asingle screw which maintains the stationary magnet part on the base andoperates a lever to position the magnet coil on the stationary magnetpart when the screw is threaded into the base.

An additional object is to provide a novel connection between thearmature and the yoke which carries the movable contacts of anelectromagnetically operated switching device which will permit theelectromagnet of the device to be readily removed and installed on abase of the device.

Further objects and features of the invention will be readily apparentto those skilled in the art from the specification and appended drawingillustrating a preferred embodiment in which:

FIG. 1 is a front view in elevation of an electromagnet switch includingan electromagnet assembly formed ac cording to the present invention.

FIG. 2 is a cross sectional view taken along line 22 in FIG. 1.

FIG. 3 is an exploded view in perspective of the components asincorporated in the switch shown in FIG. 1.

FIG. 4 is a plan view of a screw as used in the switch assembly in FIG.1.

The electromagnetic device or switch 10 shown in the drawings includes abase 12, preferably formed as a unitary part of die cast metal materialto have a set of openings 14 for mounting the device on a verticalpanel, not shown, with an electromagnet assembly 20 positioned at thelower vertical portion of the base 12. The opening 14 at the top of thebase 12 is an inverted key hole-shaped opening and the pair of openings14 at the bottom of the base are slots having exposed ends at the bottomedge of the base 12.

Positioned at the top portion of the base 12 by suitable screws 16 is aninsulating support 18 carrying spaced pairs of stationary contacts eachdesignated by a numeral 22. The respective pairs of stationary contacts22 are located to be bridged by movable contacts 24 which areresiliently supported by springs 26 on a movable contact carrier 28which is movable on the base 12. The structure of the support 18, thestationary contacts 22, and the movable contacts 24, is more fullydisclosed and described in an application for United States Patent, Ser.No. 759,382, which is concurrently filed herewith and has been assignedby the inventors Allin Schubring and Kenneth L. Paape to the assignee ofthe present invention.

The base 12 is symmetrical about a vertical center line 30 and includesat its upper portion a suitable ledge 32 and slots to receive nuts 34which receive the screws 16 to position and secure the insulated support18 to the base 12. Extending inwardly from a front wall 36 of the baseis a rectangularly shaped recess 38 having a rear wall 40. Locatedsubstantially at each of the four corners of the recess 38 are abutments42, only one of which is shown in FIG. 3, each having a top surfaceextending in a plane spaced parallel and forwardly of the rear wall 40.Extending forwardly of the front wall 36 on opposite sides of the recess38 are a pair of side walls 44 each having an inner wall 46 forming acontinuation of the sides of the recess 38 and outer walls 48 extendingperpendicular to surface portions 50 as are provided by the portions ofthe front Wall 36. The side walls 44 each have a front edge 52 extendingin a plane that is spaced forwardly of the rear wall 40.

Extending across a top portion of the recess 38 between the pair ofsidewalls 44 is a top wall or support ledge 54 having a front mountingsurface 56 coplanar with the front edges 52 and a rear surface 8 which,as shown in FIG. 2, faces and is spaced forwardly of the rear wall 40. Athreaded opening 60 located on the center line 30 extends through thetop wall 54 between the mounting surface 56 and the rear surface '58along an axis perpendicular to the rear wall 40. Extending for- Wardlyof the mounting surface 56 is a stop wall 62 which has a stop surface 64formed along an upper marginal edge of the mounting surface and anupwardly facing surface 66 spaced from the insulating support 18. Thefront surface of the wall 62 has a bore 68 located on the center line 30extending inwardly in the wall 62 along an axis perpendicular to therear wall 40. Additionally, portions of the top wall 54 have a pair ofledges 63 formed therein which extend on opposite sides of a boss 65wherein the threaded opening 60 extends and which extend throughsuitable notches 67 in the sidewalls 44. The stop surface 64 is providedwith a rectangularly shaped recess 70 which receives a shock pad 72 anda shock plate 74. The shock pad 72 and the shock plate 74 are laminatedon each other to have the shock pad positioned between the shock plate74 and the stop surface 64 when the shock pad 72 and the shock plate 74are positioned in the recess 70. The recess 70'. has a depth less thanthe combined thickness of the shock pad 72 and" the shock plate 74, sosurface portions of the shock plate project from the remaining portionsof the stop surface 64 defining the recess 70. The shock plate includesan angled portion 76 extending substantially at right angles to theportion of the shock plate 74 which is positioned in the recess 70. Theangled portion 76 has an opening 78 therein which receives a shank of arivet 80 that is driven into the bore 68 so the head portion 82 isspaced from the angled portion 76 whereby the shock plate will have alimited unrestricted movement in the recess 70.

Loosely secured in the recess 38 is an L-shaped lever 84. The lever 84is loosely maintained in the recess 38 by a pin 8-6 that extends fromthe rear wall 40- and extends to be loosely received in an opening inthe lever 84 so that a central portion 90* of the lever 84 may rotateand act as a pivot about the rear wall 40. Extending upwardly from thecentral portion 90, is an arm portion 92 which extends upwardly into thespace between the rear wall '40 and the rear surface 58. The arm 92 hasa portion aligned with the threaded opening 60 in the top wall 54.

Extending forwardly from the central portion 90 at an angle less thanperpendicular to the arm 92, the lever 84 is provided with an arm 94which is bifurcated to provide a pair of spaced fingers 96. The lever 84is formed of resilient material so the fingers 96 are capable of bendingand will act as spring members.

The electromagnet assembly 20 includes a stationary magnet part '98, amovable magnet part or armature 100, and a magnet coil 102. Thestationary magnet part 98 includes a stack of E-shaped magnet iron parts104 which are laminated upon each other and tightly held assembledbetween a pair of non-magnet iron E-shaped side plates by rivets 108.The magnet part has a pair of arms 110 extending from opposite ends of abody portion 112 with a central leg 114 extending from a central portionof the body portion 112. The arms 110 are spaced on opposite sides ofthe central leg 114 and provide flat pole faces 116 wherein shadingcoils 118 are located. Extending in the body portion 112 along an axisperpendicularly to the rear wall 40 passing through the center line 30and the threaded opening '60 is a bore or opening 120 which has adiameter greater than the diameter of the opening 60.

The armature 100 includes a stack of T-shaped magnet iron parts 122which are tightly held assembled by rivets 124 to have a central leg 126and flat pole faces 12-8 on opposite ends of body portion 130.

The body portion 130 has a tapered bore 132 extending therethrough thatis perpendicular to the rear wall 40 along an axis passing through thecenter line 30.

The coil 102 is formed with suitable coil windings, not shown, which areencapsulated in a shell formed of epoxy or other suitable materialtoprovide a generally rectangular body having a pair of spaced endswhich respectively provide an upper end 134, a lower end 136, a rearwall 138, sidewalls and a front wall 142 which has a raised portionproviding an anchorage for a pair of wire connecting terminals 144 thatare electrically connected to the windings of the coil 102.Additionally, the coil 102 has a rectangular opening or bore 147extending between the upper and lower ends 134 and 136, which receivesthe legs .114 and 126 with clearance. Further, the width between thesidewalls 140 is less than the distance between the sidewalls 44.

The movable contact carrier 28 is formed of a suitable impact resistantmolded material to have a pair of spaced side legs 146, a lower member148 bridging the bottom end portions of the side legs 146 and a movablecontact carrier 150 bridging the top portions of the legs 146 to providea substantially rectangularly shaped opening 152 between the side legs146, the lower member 148 and the contact carrier 1 50'. The side legs146 are spaced so the portions thereof forming the opening are adjacentand guided by the outer walls 48 while front surface portions 154 aresubstantially coplanar with the front edges 52 as the rear surfaceportions 156 thereof slide on the surface portions 50 of the base 12.The contact carrier 150, which positions the movable contacts asdescribed in the Schubring et al. application supra, has a lower surfaceportion 158 resting upon the upwardly facing surface 66 when the magnetassembly 20 is de-energized. Secured in the lower member 148, as bybeing embedded therein when the contact carrier 28 is molded, is a pin160' which is located on the center line 30 and projects vertical to aplane passing through the front edges 52 above the front surface of thelower member 148. The pin 160 is loosely received in the bore .132 toprovide a connection between the armature 100 and the contact carrier 28which will permit the armature 100 to have a limited universal typemovement relative to the contact carrier 28. Additionally extendingforwardly of the side legs 146 are projections 161 which may be used toactuate auxiliary switch units, not shown, for the purposes and in themanner as will be readily apparent to those skilled in the art to whichthe present invention pertains.

Also included in the structure of the switch 10 is a guide plate 162, afastening screw 164 and a spring 166. The guide plate 162, in theembodiment shown, is formed as a die cast member although other methodsof manufacture and materials may be used in its formation, is generallyshaped to conform to the configuration of the stationary magnet part 98and may include, on a face which engages the magnet part, suitabledepressions, not shown, to receive the heads of the rivets 108. Theportion of the guide plate 162 corresponding to the body portion 112 isprovided with a threaded opening which is aligned with the threadedopening 60 when the guide plate is positioned on the mounting surface 56by suitable projections, not shown, which are received in the ledges 63and embrace the boss 65. Additionally, the guide plate is provided witha notch 172 which embraces portions of the stop wall 62 and notches 174which provide clearance for the movement of projections 161. The screw164 has a head portion 176 on one end and a tip portion 178 on itsopposite end. Extending from the head portion 176 is a shank 180 havinga diameter to be Ioosely received in the opening 120- and a reduceddiameter shank portion 182 which is loosely screwed in the threadedopening 170 in the guide plate 162 after a threaded portion 184 locatedbetween the shank 182 and the tip 178 is threaded through the opening170. The threaded portion 184, which has an outer diameter greater thanthe tip portion 178 and the shank portion 182, when threaded into theopening 60 positions the tip portion 178 in a position to engage the arm92 of the L- shaped lever member 84. The screw 164, when installed, ismaintained against loosening rotation by the spring 166 which ispositioned under compression between the head 176 and the front surfaceof the body portion 112.

The switch is assembled by initially installing the laminated shockplate 74 and shock pad 72 on the top wall 62 by inserting the rivet 80into the bore 68 and then installing the insulating support 18, with thestationary contacts 22 assembled thereon, and the movable contactcarrier 28, with the movable contacts 24 thereon, onto the base 12. Theinsulating support 18 is maintained in position on the base 12 by theledge 32 when the screws 16 are threaded into the nuts 34. The movablecontact carrier 28 is positioned on the base 12 by projections 184 whichextend from the rear face of the carrier 28 into forwardly facinggrooves 186 in the base 12 so the side legs 146 are guided by thesidewalls 44 and the movable contact carrying portion 150 of the carrier28 is positioned between the upwardly facing surface 66 and theinsulating support 18 while the lower member 148 causes the pin 160 toextend forwardly of the base 12.

The components of the electromagnet assembly are then assembled as aunit by assembling the spring 166 on the shank 180 adjacent the head 176of the screw 164 and passin the tip 178, the threaded portion 184 andthe shank through the opening 120 so the shank 180 is loosely receivedin the opening 120 while the spring 166 is positioned between the head176 and the front surface of the body portion 112. The guide plate 162is then positioned onthe rear surface of the stationary magnet part 98when the screw 164 is completely threaded through the opening 170 in theguide plate 162 so that the reduced diameter shank 182 is looselyreceived in the opening 170 to prevent disassembly of the guide plate162 and the screw 164 from the stationary magnet part 98. The coil 102is then positioned on the assembled guide plate 162 and the stationarymagnet part 98 by inserting the central leg 114 into the opening 147 ofthe coil so the body portion 112 is adjacent the upper end 134 of thecoil and the arms 110 are external of the sidewalls 140 to position thepole faces 116 at the lower end 136. The armature 100 is then positionedrelative to the coil 102 and magnet part 98 by inserting the central leg126 in the opening 147 so the body portion 130 is adjacent the lower end136 of the coil 102 and the pole faces 128 are aligned with the polefaces 116.

The assembled electromagnet including the spring 166, the screw 164, thestationary magnet part 98, the guide plate 162, the coil 102 and thearmature 100 are then positioned on the base 12 whereon the insulatingsupport 18 and the movable contact carrier 28 have been previouslyassembled by placing the electromagnet assembly in a position whereinthe body portion 112 is. aligned to be adjacent the shock plate 74 thefingers 96 are aligned to be adjacent the lower end 136 of the coil 102,the bore 132 is aligned with the pin 160, the guide plate 162 ispositioned to engage the front edges 52 and the tip portion 178 isreceived in the threaded opening 60. The electromagnet assembly 20 whenmoved to its proper position on the base 12 will have portions of thecoil 102 positioned in the recess 38 with portions of the rear wall 138resting on the abutments 42, the armature 100 resting on the lowermember 148, the body portion 112 resting on the mounting surface 56 andengaging the shock plate 74 while the rear surface of the guide plate162 is positioned adjacent the front surfaces 154 to confine the movablecontact carrier 28 on the base 12. The

assembly of the electromagnet assembly 20 on the base 12 is completedwhen the screw 164 is tightened in the threaded opening 60. As the screw164 is tightened, the spring 166 will be compressed against the bodyportion 112 to resiliently maintain the stationary magnet part 98 on themounting surface 56 while the tip portion 178 of the screw 164 engagesthe arm 92 and rotates the lever 84 about its central portion so thefingers 96, which straddle the bore 147, resiliently maintain the coil102 in position on the stationary magnet part 98 which is also urged bythe pressure exerted by the fingers 96 upwardly into a tight engagementwith the shock plate 74.

The electromagnet assembly may be readily removed from the base 12 byunthreading the fastening screw 164 from the threaded opening 60 so thatthe electromagnet assembly 20, including the guide plate 162, the screw164, the stationary magnet part 98, the armature 100 and the coil 102may be removed as a unit. When the electromagnet assembly 20 is thusremoved, the coil 102 or any of the magnet parts may be readily replacedor inspected and re-installed on the base in the manner previouslydescribed. The removal and insertion of the electromagnet assembly 20 isfacilitated by the presence of the metal shock plate which permits themetal body portion 112 to slide with minimum friction across the metalshock plate 74 and the loose connection between the bore 132 and the pin160.

When the switch 10 is mounted on the vertical panel and theelectromagnet assembly 20 is de-energized, the'movable contact carryingportion of the movable contact carrier 28 will rest upon the upwardlyfacing surface 66. When the coil 102 is energized, the armature 100which is attracted by the stationary magnet part 98, moves the movablecontact carrier 28 upwardly and causes the pole faces 128 to engage thepole faces 116 with a firm seating engagement. The firm engagementbetween the pole faces 128 and 116 is a result of the movable connectionprovided between the pin and the bore 132. The shock accompanying theengagement between the armature 100 and the stationary magnet part 98 istransmitted by the body portion 112 through the metal shock plate 74 tothe shock pad 72. The metal shock plate 74 is loosely mounted by pin 80in the bore 68 so as to have limited movement so that the shockaccompanying the movement of the stationary magnet part 98 istransmitted to the shock pad 72. The shock pad 72 is formed of apolyurethane material which is compounded in a manner well known tothose skilled in the art to possess shock absorbing power and vibrationdampening characteristics. As is well known to a polymer chemist,polyurethane material is a polym-eric material resulting from thecondensation polymerization of diisocyanatesand polyols, and thus isparticularly suited to absorb the shock accompanying the energization ofthe electromagnet so as to minimize the phenomena known as contactbounce of the switch. As clear- 1y shown, a considerable portion of themetal area of the stationary magnet part 98 is in contact with the shockplate 74 and portions of the base 12. This large area of metal-to-metalcontact between the magnet part 98 and the base 12 will cause the heatgenerated within the stationary magnet part 98 when the coil 102 isenergized, to be rapidly dissipated by the base 12.

While certain preferred embodiments of the invention have beenspecifically disclosed, it is understood that the invention is notlimited thereto, as many variations will be readily apparent to thoseskilled in the art and the invention is to be given its broadestpossible interpretation within the terms of the following claims.

What is claimed is:

1. In an electromagnetically operated device, the combinationcomprising: a base having a rear wall, a support ledge providing amounting surface spaced forwardly of the rear wall, a threaded openingin the support ledge extending perpendicular to the rear wall and a stopwall extending forwardly and perpendicular to the mounting surface alongan ,upper marginal edge f the support ledge, an electromagnet includinga stationary magnet part and a mag netcoil, said magnet part having abody portion jtixtaposed to the stop walland the mounting surface and anopening therein aligned with the opening in the support ledge, 'saidmagnet coil having a pair of spaced ends .ex-

tending perpendicular to the rear wall with a first one of said pair ofends juxtaposed to, the body portion and a secondone of said pair ofends disposed remotely from I the stop wall and the body portion .ofthestationary magnet part, and a means for securing the bodyportion on themounting surface and tightly pressing the juxtaposed portions of thecoil, the body portion, and the stop 1 wall into engagement with eachother, said means comprising: a lever having a central portion pivotedon the rear, wall, a first arm portion engaging the second end of.

the coil and a second arm portionextending into a space between therear, wall and support ledge in alignment with the openings in the ,bodyportion and thesupport ledge, andathreaded member having a head portiondisposed externally of the body portion, a shank portion extending inthe opening in the body portion, a threaded portion received in the,threaded opening andatip portionengag; ing the second arm portion ofthe lever for securing the,

body portion on the mounting, surface and rotating the lever about thepivoted central portion and moving the firstarm :portion against thesecond face of the coil to press the, juxtaposed portions of the coil,the stationary magnet partand the stop wall in tight engagement witheach other whenfthe thread portion is threaded into the threaded p n 3 t2, Inan elecromagnetically operated device, the com bination comprising:a base having a rear wall, a pair of forwardlyprojecting parallel spacedsidewalls witheach ginal edgeofithe rnounting surface, an electromagnetinv eluding a stationary magnet part, andia magnet coil, said,stationary magnet part having 'a body,,portionjuxtaposed to, the stopwalland the mountingsurface, anopeningin the body portion aligned withtheopening in the support ledge and,arm portions positioned on, thefront ends of the sidewalls, said rnagnetcoilhaving a pair of spacedends extending perpendicular totherear wall with a first one of ,said,pair of'ends juxtaposed to, the body portion and a second one of saidpair of ends ,disposed remotely from the stop wallof thebase and thebody portion of the stationary magnet part, and a means for securing thebody portionon. the. mounting surface and tightly pressing thejuxtaposed portions of the coil,, thebody portion and the stop wall intoengagement with each other, said means comprising: a lever having avcentral portion pivoted on the rear wall, a first armportion engagingthe second end of the coil and a second arm portion extending into thespace between theHre-ar wall and the rear surface in alignment withthealigned; openings in the body portion and the top,wall, and a threadedmember having a head,

portion disposedexternally of the body portion, ashank portion extendingintheopening in the body ,porti on, a

threaded portion received in the threaded opening and, a

tip portion engaging the second arm portion of the lever for securingthe body portion on the front mounting surface and rotating the leverabout the P VQ fll nfi PO tion and movingthe first arm portion againstthe second. end of the coil to press the juxtaposed portions of thecoil, the stationary magnet part and the stop wall in tight engagementwith eachother when the thread portion is threaded into the threaded;opening:

3. The combination as recited in claim" 1- wherein a;-

spring positioned between the headportion and the'body portion of themagnet part resiliently maintains the body portion on the mountingsurface. r

4, The combination as recited in claim 1-wherein =ametalplate and apolymeric member are positioned between the body portion and the stopwallto absorb shock accompanying the energization ,of' theeleotromagnet.

5. The combination as recited in claim 1 wherein the magnet coilincludes a bore extending between the pairof ends and the first armportion of, the lever isbifurcated to provide a Pair of spaced fingerswhich are positionedon opposite sides of the bore exposed by the secondend of the coil.

.6. ,The combination as recited in claim 2 wherein the electromagnetincludes an armature that is movable 'into an engaging position withportions of the stationary magnet part upon,energization of the magnetcoil and the velectromagnetically operated device includes a movablecontact carrier havinga pair of spaced arms movable;

along the spaced parallelside walls. and an end wall extending betweenthe pairof spaced aims and a connection between the armature and theContact carrier includes a single pin that extends through a centrallylocated opening in the armature. t

1. The combination as, recited in claim 2 wherein the electromagnetincludes-an armature that is movable into an engaging position-withportions of the stationary magnet partupon energizationof the magnetcoil and the electromagneti cally operated device includes .a movable,

contact carrierhaving, a pair of ,spaced arms movable along the spacedparallel side walls and ,a, Pair of spaced end walls extending betweenthe pairof spaced arms, a connection between the armature and thecontact carrier includes asingle pin carried by one of the pair Of'spaced end walls that extends through ,a centrally, located opening inthe armature andthe-othe r ofgsaid pairof end walls 1s arranged toengage the stop wall when the electromagnet is de-energized.

8. The combination: as ,recited inclaim; 4, wherein the polymeric memberis positioned between the metal plate and the stop wall.;- s, 1,1,1 1, 1,5

9. The combination as recited in.,claim 2 wherein the stationary magnet,part is E-shaped and-themagnet coil includes abore extending betweenthe; spaced. ends which,

is receivedv by a central-leg ofthestationary magnet part while a pairof outer legs of the. stationary magnet rest 1 upon the front edges ofthe spaced sidewalls of ,thebase. 10. The combination as recited inclaim 8 wherem the polymeric membersis formed as a sheet-like part ofpolyurethane material. References Cited I UNITED STATES PATENTS 4/1965'McGary' 335-402v 3,179,771 3,339,161, 8/1967 Conner 335-493. 3,406,36110/1968 Mauviel 33s 2o2 G. HARRIS, Primary Examiner H. BROOME, AssistantExaminer Us. 01. XRQ 335-132

